mm: replace get_user_pages() write/force parameters with gup_flags

This removes the 'write' and 'force' from get_user_pages() and replaces
them with 'gup_flags' to make the use of FOLL_FORCE explicit in callers
as use of this flag can result in surprising behaviour (and hence bugs)
within the mm subsystem.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

15 files changed, 36 insertions, 22 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 887483b8b818..dcaf691f56b5 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -555,10 +555,13 @@ struct amdgpu_ttm_tt {
 int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 {
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
-	int write = !(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY);
+	unsigned int flags = 0;
 	unsigned pinned = 0;
 	int r;
 
+	if (!(gtt->userflags & AMDGPU_GEM_USERPTR_READONLY))
+		flags |= FOLL_WRITE;
+
 	if (gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) {
 		/* check that we only use anonymous memory
 		   to prevent problems with writeback */
@@ -581,7 +584,7 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages)
 		list_add(&guptask.list, &gtt->guptasks);
 		spin_unlock(&gtt->guptasklock);
 
-		r = get_user_pages(userptr, num_pages, write, 0, p, NULL);
+		r = get_user_pages(userptr, num_pages, flags, p, NULL);
 
 		spin_lock(&gtt->guptasklock);
 		list_del(&guptask.list);
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 455268214b89..3de5e6e21662 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -566,7 +566,8 @@ static int radeon_ttm_tt_pin_userptr(struct ttm_tt *ttm)
 		uint64_t userptr = gtt->userptr + pinned * PAGE_SIZE;
 		struct page **pages = ttm->pages + pinned;
 
-		r = get_user_pages(userptr, num_pages, write, 0, pages, NULL);
+		r = get_user_pages(userptr, num_pages, write ? FOLL_WRITE : 0,
+				   pages, NULL);
 		if (r < 0)
 			goto release_pages;
 
diff --git a/drivers/gpu/drm/via/via_dmablit.c b/drivers/gpu/drm/via/via_dmablit.c
index 7e2a12c4fed2..1a3ad769f8c8 100644
--- a/drivers/gpu/drm/via/via_dmablit.c
+++ b/drivers/gpu/drm/via/via_dmablit.c
@@ -241,8 +241,8 @@ via_lock_all_dma_pages(drm_via_sg_info_t *vsg,  drm_via_dmablit_t *xfer)
 	down_read(&current->mm->mmap_sem);
 	ret = get_user_pages((unsigned long)xfer->mem_addr,
 			     vsg->num_pages,
-			     (vsg->direction == DMA_FROM_DEVICE),
-			     0, vsg->pages, NULL);
+			     (vsg->direction == DMA_FROM_DEVICE) ? FOLL_WRITE : 0,
+			     vsg->pages, NULL);
 
 	up_read(&current->mm->mmap_sem);
 	if (ret != vsg->num_pages) {
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index c68746ce6624..224ad274ea0b 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -94,6 +94,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	unsigned long dma_attrs = 0;
 	struct scatterlist *sg, *sg_list_start;
 	int need_release = 0;
+	unsigned int gup_flags = FOLL_WRITE;
 
 	if (dmasync)
 		dma_attrs |= DMA_ATTR_WRITE_BARRIER;
@@ -183,6 +184,9 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	if (ret)
 		goto out;
 
+	if (!umem->writable)
+		gup_flags |= FOLL_FORCE;
+
 	need_release = 1;
 	sg_list_start = umem->sg_head.sgl;
 
@@ -190,7 +194,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 		ret = get_user_pages(cur_base,
 				     min_t(unsigned long, npages,
 					   PAGE_SIZE / sizeof (struct page *)),
-				     1, !umem->writable, page_list, vma_list);
+				     gup_flags, page_list, vma_list);
 
 		if (ret < 0)
 			goto out;
diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index 6c00d04b8b28..c6fe89d79248 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -472,7 +472,7 @@ int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
 		goto out;
 	}
 
-	ret = get_user_pages(uaddr & PAGE_MASK, 1, 1, 0, pages, NULL);
+	ret = get_user_pages(uaddr & PAGE_MASK, 1, FOLL_WRITE, pages, NULL);
 	if (ret < 0)
 		goto out;
 
diff --git a/drivers/infiniband/hw/qib/qib_user_pages.c b/drivers/infiniband/hw/qib/qib_user_pages.c
index 2d2b94fd3633..75f08624ac05 100644
--- a/drivers/infiniband/hw/qib/qib_user_pages.c
+++ b/drivers/infiniband/hw/qib/qib_user_pages.c
@@ -67,7 +67,8 @@ static int __qib_get_user_pages(unsigned long start_page, size_t num_pages,
 
 	for (got = 0; got < num_pages; got += ret) {
 		ret = get_user_pages(start_page + got * PAGE_SIZE,
-				     num_pages - got, 1, 1,
+				     num_pages - got,
+				     FOLL_WRITE | FOLL_FORCE,
 				     p + got, NULL);
 		if (ret < 0)
 			goto bail_release;
diff --git a/drivers/infiniband/hw/usnic/usnic_uiom.c b/drivers/infiniband/hw/usnic/usnic_uiom.c
index a0b6ebee4d8a..1ccee6ea5bc3 100644
--- a/drivers/infiniband/hw/usnic/usnic_uiom.c
+++ b/drivers/infiniband/hw/usnic/usnic_uiom.c
@@ -111,6 +111,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 	int i;
 	int flags;
 	dma_addr_t pa;
+	unsigned int gup_flags;
 
 	if (!can_do_mlock())
 		return -EPERM;
@@ -135,6 +136,8 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 
 	flags = IOMMU_READ | IOMMU_CACHE;
 	flags |= (writable) ? IOMMU_WRITE : 0;
+	gup_flags = FOLL_WRITE;
+	gup_flags |= (writable) ? 0 : FOLL_FORCE;
 	cur_base = addr & PAGE_MASK;
 	ret = 0;
 
@@ -142,7 +145,7 @@ static int usnic_uiom_get_pages(unsigned long addr, size_t size, int writable,
 		ret = get_user_pages(cur_base,
 					min_t(unsigned long, npages,
 					PAGE_SIZE / sizeof(struct page *)),
-					1, !writable, page_list, NULL);
+					gup_flags, page_list, NULL);
 
 		if (ret < 0)
 			goto out;
diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
index f300f060b3f3..1db0af6c7f94 100644
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -156,6 +156,7 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
 {
 	unsigned long first, last;
 	int err, rw = 0;
+	unsigned int flags = FOLL_FORCE;
 
 	dma->direction = direction;
 	switch (dma->direction) {
@@ -178,12 +179,14 @@ static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
 	if (NULL == dma->pages)
 		return -ENOMEM;
 
+	if (rw == READ)
+		flags |= FOLL_WRITE;
+
 	dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
 		data, size, dma->nr_pages);
 
 	err = get_user_pages(data & PAGE_MASK, dma->nr_pages,
-			     rw == READ, 1, /* force */
-			     dma->pages, NULL);
+			     flags, dma->pages, NULL);
 
 	if (err != dma->nr_pages) {
 		dma->nr_pages = (err >= 0) ? err : 0;
diff --git a/drivers/misc/mic/scif/scif_rma.c b/drivers/misc/mic/scif/scif_rma.c
index e0203b1a20fd..f806a4471eb9 100644
--- a/drivers/misc/mic/scif/scif_rma.c
+++ b/drivers/misc/mic/scif/scif_rma.c
@@ -1396,8 +1396,7 @@ retry:
 		pinned_pages->nr_pages = get_user_pages(
 				(u64)addr,
 				nr_pages,
-				!!(prot & SCIF_PROT_WRITE),
-				0,
+				(prot & SCIF_PROT_WRITE) ? FOLL_WRITE : 0,
 				pinned_pages->pages,
 				NULL);
 		up_write(&mm->mmap_sem);
diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/grufault.c
index a2d97b9b17e3..6fb773dbcd0c 100644
--- a/drivers/misc/sgi-gru/grufault.c
+++ b/drivers/misc/sgi-gru/grufault.c
@@ -198,7 +198,7 @@ static int non_atomic_pte_lookup(struct vm_area_struct *vma,
 #else
 	*pageshift = PAGE_SHIFT;
 #endif
-	if (get_user_pages(vaddr, 1, write, 0, &page, NULL) <= 0)
+	if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= 0)
 		return -EFAULT;
 	*paddr = page_to_phys(page);
 	put_page(page);
diff --git a/drivers/platform/goldfish/goldfish_pipe.c b/drivers/platform/goldfish/goldfish_pipe.c
index 07462d79d040..1aba2c74160e 100644
--- a/drivers/platform/goldfish/goldfish_pipe.c
+++ b/drivers/platform/goldfish/goldfish_pipe.c
@@ -309,7 +309,8 @@ static ssize_t goldfish_pipe_read_write(struct file *filp, char __user *buffer,
 		 * much memory to the process.
 		 */
 		down_read(&current->mm->mmap_sem);
-		ret = get_user_pages(address, 1, !is_write, 0, &page, NULL);
+		ret = get_user_pages(address, 1, is_write ? 0 : FOLL_WRITE,
+				&page, NULL);
 		up_read(&current->mm->mmap_sem);
 		if (ret < 0)
 			break;
diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index 436dfe871d32..9013a585507e 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -892,7 +892,8 @@ rio_dma_transfer(struct file *filp, u32 transfer_mode,
 		down_read(&current->mm->mmap_sem);
 		pinned = get_user_pages(
 				(unsigned long)xfer->loc_addr & PAGE_MASK,
-				nr_pages, dir == DMA_FROM_DEVICE, 0,
+				nr_pages,
+				dir == DMA_FROM_DEVICE ? FOLL_WRITE : 0,
 				page_list, NULL);
 		up_read(&current->mm->mmap_sem);
 
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
index c29040fdf9a7..1091b9f1dd07 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
@@ -423,8 +423,7 @@ create_pagelist(char __user *buf, size_t count, unsigned short type,
 		actual_pages = get_user_pages(task, task->mm,
 				          (unsigned long)buf & ~(PAGE_SIZE - 1),
 					  num_pages,
-					  (type == PAGELIST_READ) /*Write */ ,
-					  0 /*Force */ ,
+					  (type == PAGELIST_READ) ? FOLL_WRITE : 0,
 					  pages,
 					  NULL /*vmas */);
 		up_read(&task->mm->mmap_sem);
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index e11c0e07471b..7b6cd4d80621 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -1477,8 +1477,7 @@ dump_phys_mem(void *virt_addr, uint32_t num_bytes)
 		current->mm,              /* mm */
 		(unsigned long)virt_addr, /* start */
 		num_pages,                /* len */
-		0,                        /* write */
-		0,                        /* force */
+		0,                        /* gup_flags */
 		pages,                    /* pages (array of page pointers) */
 		NULL);                    /* vmas */
 	up_read(&current->mm->mmap_sem);
diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
index 60bdad3a689b..150ce2abf6c8 100644
--- a/drivers/virt/fsl_hypervisor.c
+++ b/drivers/virt/fsl_hypervisor.c
@@ -245,8 +245,8 @@ static long ioctl_memcpy(struct fsl_hv_ioctl_memcpy __user *p)
 	/* Get the physical addresses of the source buffer */
 	down_read(&current->mm->mmap_sem);
 	num_pinned = get_user_pages(param.local_vaddr - lb_offset,
-		num_pages, (param.source == -1) ? READ : WRITE,
-		0, pages, NULL);
+		num_pages, (param.source == -1) ? 0 : FOLL_WRITE,
+		pages, NULL);
 	up_read(&current->mm->mmap_sem);
 
 	if (num_pinned != num_pages) {